1. Field of the Invention
The present invention relates generally to surgical devices for introduction into a patient in minimally invasive surgery. More particularly, the present invention relates to medical endoscopes and, even more particularly, to a continuous flow endoscope sheath assembly.
2. Background Art
Minimally invasive surgery reduces patients"" surgery-induced trauma, pain, and infection risk. Minimally invasive surgery typically is performed through one or more portals, such as a body orifice or a small incision formed in the patient""s body. The portals provide for introduction of surgical devices, such as endoscopes that allow viewing of the surgical site. The surgical instruments enable examination, therapeutic action, and operative actions. The therapeutic actions include, among other things, irrigating, suctioning, cutting, cauterizing, coagulating, vaporizing, retracting, stapling, and sampling tissue. The instruments may also provide operative actions such as distention of a body cavity, substance ingress, and substance egress.
By minimizing invasiveness, procedures are safer and atraumatic, patients recover more quickly, hospital stays are shortened, and health care costs may be decreased. Accordingly, minimizing invasiveness continues to be of importance, and there is a continuing need for devices and methods that achieve this objective.
One significant barrier to further minimization of invasiveness is that in many procedures, the instruments must have fluid inflow and outflow channels. These channels effectively add to the outer diameter of the instruments. For example, known endoscopic instruments provide inflow/outflow through an assembly of concentric sheaths that define channels for inflow and outflow of fluids to and from the operative or surgical site. For example, the fluid may be an irrigating solution that helps maintain a clear view of the site for the physician. Certain known irrigating systems provide continuous and simultaneous inflow and outflow. These systems are known as xe2x80x9ccontinuous flowxe2x80x9d systems.
The known continuous flow endoscope systems generally introduce an irrigating fluid into the surgical site from an external source. For this purpose, the endoscope has an inflow channel defined by the inner surface of the inner sheath. The fluid passes through the channel and exits the distal end of the sheath to irrigate the operative site. Fluid at the surgical site may be withdrawn through an outflow channel defined by the outer surface of the inner sheath and the inner surface of a surrounding outer sheath. The outflow channel initiates at the distal end (front end) of the instrument and transports fluid to an exit point at the proximal end of the outer sheath.
Examples of continuous flow systems include: U.S. Pat. Nos. 3,835,842; 5,392,765; 3,835,842; 4,920,961 (discloses a latching system for connecting inner and outer sheaths to each other and for connecting the inner sheath to a base element); 5,486,155 (discloses a rotatable continuous flow endoscope sheath); 5,320,091; and 5,392,765 (discloses a continuous flow cystoscope with a front top inlet). The foregoing patents are incorporated herein by reference in their entireties for all purposes, and more particularly to show certain devices that could be adapted to include the features of the present invention. (This incorporation by reference is not intended to be an admission that any referenced patent is prior art that would render claims appended hereto unpatentable.)
Looking more particularly at the known devices, the outflow channel has a main distal aperture for withdrawing fluid. The aperture may be defined by the distal end points of the inner sheath or outer sheath (whichever has its distal end in a proximal position relative to the distal end of the other) and the points on the inner or outer sheath that are on common perpendicular lines off the longitudinal axis of the outflow channel. In other words, if the inner sheath is recessed within the outer sheath, and all points on the distal end of the inner sheath lie in a single plane transverse to the longitudinal axis of the inner sheath, then the aperture for the outflow channel is defined by the transverse plane through the inner sheath and extending through the surrounding outer sheath. This is the case, for example, in U.S. Pat. No. 3,835,842, where the distal end of the outer sheath extends distally beyond the distal end of the inner sheath (represented in FIG. 9). In other cases, as seen in U.S. Pat. No. 4,132,227 (represented in FIG. 10), the distal end of the inner sheath extends distally beyond the distal end of the outer sheath. The points on the distal end of the outer sheath do not lie in a single plane. Therefore, the outflow aperture does not have points that lie in a single transverse plane, i.e., the aperture initiates at a distal location and terminates at a proximal location. A significant drawback of this arrangement is that the aperture, which generally has an annular profile because it is defined by the space between sheaths, has a limited area for outflow. Increasing the space between sheaths to increase the outflow area would necessitate a corresponding increase in the outer diameter of the sheath assembly. This, of course, runs contrary to the objective of minimizing invasiveness.
There has been some effort to address the foregoing problem, but it has not been adequate. In known devices, in addition to a main outflow aperture at the front end of the device, the outer surface of the outer sheath has one or more lateral outflow apertures for passing fluid from the exterior of the outer sheath into the outflow channel. It is significant that in the known devices, these secondary outflow apertures on the outer sheath are disposed proximal (behind) the inflow aperture at the distal (front) end of the inner sheath. This is largely because the outflow holes would necessarily be positioned sufficiently proximal from the distal structure of the inner sheath so as to provide for unimpeded outflow through the holes and into the outflow channel between inner and outer sheaths. As a consequence, these lateral outflow holes generally lie well proximal to the inflow aperture. Unfortunately, there are inherent, unresolved disadvantages in tip portions having outflow apertures disposed proximal to the inflow aperture. For example, tissue or debris at the surgical site may press against the lateral outflow apertures, blocking them. This reduces outflow capacity.
In endoscopes such as resectoscopes, which are used with electrosurgical throughput devices, such as cutting, coagulating, or vaporizing electrodes, the distal tip portion of the inner or outer sheath assembly includes a dielectrical tip. The dielectrical tip insulates the electrode element from the outer and inner sheaths, which are generally made of electrically conductive metal. In general, the tip is a tube-like extension of the outer or inner sheath. However, the tip may take other configurations, such as a partial tube, beak, shield, etc. In the known devices, the insulative tip does not provide lateral apertures for outflow. Therefore, lateral outflow apertures in the known devices are situated even further behind the inflow aperture, and provide inadequate outflow at the distal tip portion of the endoscope. This is particularly disadvantageous where such instruments are used in tight anatomical spaces.
Another disadvantage of having a dielectrical tip placed on the end of the inner sheath is that common dielectrical materials are brittle and prone to fracturing when the inner sheath is physically withdrawn from the outer sheath.
For at least the foregoing reasons, there is a significant need for improved outflow systems in endoscopes and other invasive medical instruments requiring outflow functions, and particularly in endoscopes used with electrosurgical throughput devices where dielectrical tips must be used.
The present invention overcomes the aforementioned disadvantages by providing an improved outflow mechanism in a tip portion in an assembly of an inner and outer sheath. One significant advantage of the present invention is its improved mechanism for outflow in tight anatomical passages. In certain embodiments, another significant advantage is that, without compromising outflow efficiency, the dielectrical tip may be placed on the outflow sheath where it is much less prone to damage or fracture from the assembly and disassembly of the inner sheath from outer sheath. Placement of the dielectrical tip on the outer sheath also allows for a heavier wall thickness of the distal aperture of the sheath thereby affording a less sharp and traumatic entry through the patient""s orifice and tissue.
More particularly, in one possible embodiment the present invention is directed to an assembly of sheaths for use in a medical instrument such as an endoscope. The assembly includes an outer sheath and inner sheath for providing inflow and outflow of fluids at a surgical site. In the assembly, an outer sheath is disposed about at least a portion of an inner sheath, and an outflow channel is disposed between the inner sheath and the outer sheath. The assembly further includes an outflow conduit with an outflow aperture initiating in an outer wall at the distal end of the assembly. The outflow conduit is disposed generally in a longitudinal direction and communicates with the more proximal outflow channel formed between the outer sheath and inner sheath so that fluid may be directed from the outflow conduit into the outflow channel.
In the foregoing assembly, the outflow conduit may initiate in a distal tip portion of the sheath in a position distal to a main inflow hole for the inner sheath assembly. In the assembly, the outflow aperture may initiate in a distal tip portion of a lateral surface of the outer sheath and merge into the outflow channel at a position proximal to the inflow hole. The inflow hole may comprise an opening at the distal end of the inner sheath. In the assembly, the outer sheath may comprise a tube and a dielectrical tip element, the tip element being affixed to the distal end of the tube. In the assembly, the tip element may have a distal portion that extends distally from within the outer tube and a proximal portion affixed to an inner surface of the outer tube, the outflow conduit being defined at least in part by a space between the proximal portion of the tip element and an inner surface of the outer tube. In the assembly, there may be a plurality of outflow conduits disposed circumferentially about the distal tip of the assembly in a position proximal to the inflow hole. In the assembly, there may be one or more thru-holes disposed in the outer surface of the assembly distal to the inflow hole at the distal end of the inner sheath. In the assembly, the tip element may comprise a ceramic material.
In another possible embodiment, the present invention is directed to a medical endoscope having an outer sheath surrounding at least a portion of an inner sheath and an outflow channel disposed therebetween. The inner sheath has an inflow hole at its distal end in an inflow channel; the outer sheath has a distal tip portion. At least one outflow conduit is disposed in an outer surface of the tip portion, the outflow conduit communicating with the outflow channel. The conduit initiates with an inflow aperture disposed on the surface of the distal tip portion at a position distal to the inflow hole at the inner sheath.
In the foregoing endoscope, the distal tip portion may include a section comprising a dielectrical material. In the endoscope, the section of the tip portion may comprise a dielectrical tip element affixed to the distal end of the inner or outer sheath. The endoscope may further include a working element. The working element may hold the outer and inner sheaths in a position such that the distal end of the inner sheath is proximal the outflow conduit. The working element may include means for communicating fluid to the inflow hole through an inflow channel in the inner sheath. The working element may include a channel for inserting a throughput device through an opening at the proximal end of the instrument. The channel may comprise the inflow channel of the inner sheath. The endoscope of the foregoing embodiment may include a telescope, electrode, and/or other throughput devices as components of the assembly. In one possible variation, the endoscope is a resectoscope.
In another possible embodiment, the present invention is directed to a method of constructing a medical endoscope. The method is carried out by providing an inner sheath and outer sheath and assembling the two such that for at least a portion of the inner sheath, an outflow channel is disposed between the inner sheath and outer sheath, the assembly having an outflow conduit with an outflow aperture initiating in an outer wall at the distal end of the assembly, the conduit being disposed generally in a longitudinal direction and communicating with the outflow channel formed between the outer sheath and inner sheath so that fluid may be directed from the outflow conduit into the outflow channel.
In the foregoing method, the outflow conduit may initiate in a distal tip portion of the sheath in a position distal to a main inflow hole for the sheath assembly. In the method, the outflow aperture may initiate in a distal tip portion of a lateral surface of the outer sheath and merges into the outflow channel at a position proximal to the inflow hole. In the method, the inflow hole may include an opening at the distal end of the inner sheath. In the method, the outer sheath may include a tube and a dielectrical tip, the tip element being affixed to the distal end of the tube. In the method, the tip element may have a distal portion that extends distally from within the outer tube and a proximal portion affixed to an inner surface of the outer tube, the outflow conduit being defined at least in part by a space between the proximal portion of the tip element and an inner surface of the outer tube. In the method, there may be a plurality of outflow conduits disposed circumferentially about the distal tip of the assembly in a position proximal to the inflow hole. In the method, one or more thru-holes may be disposed in the outer surface of the assembly distal to the inflow hole at the distal end of the inner sheath. In the method, the tip element may comprise a ceramic material.
In another possible embodiment, the present invention is directed to a method of using a medical instrument in a surgical procedure. The method provides for inserting into a surgical site of a patient an assembly of an outer sheath and inner sheath for providing inflow and outflow of fluids at a surgical site. In the assembly, the outer sheath is disposed about at least a portion of the inner sheath, and an outflow channel is disposed between the inner sheath and outer sheath. The assembly has an outflow conduit with an outflow aperture initiating in an outer wall at the distal end of the assembly. The outflow conduit is disposed generally in a longitudinal direction and communicating with the outflow channel formed between the outer sheath and inner sheath so that fluid may be directed into the outflow channel from the outflow conduit. The outflow conduit initiates in a distal tip portion of the sheath in a position distal to a main inflow hole for the sheath assembly withdrawing fluid through the outflow channel via the outflow conduit and associated outflow aperture.
In the foregoing method, the conduit may initiate in a distal tip portion of the sheath in a position distal to a main inflow hole for the sheath assembly. In the method, the outflow aperture may initiate in a distal tip portion of a lateral surface of the outer sheath and merges into the outflow channel at a position proximal to the inflow hole. In the method, the inflow hole may comprise an opening at the distal end of the inner sheath. In the method, the outer sheath may comprise a tube and a dielectrical tip element, the tip element being affixed to the distal end of the tube. In the method, the tip element may have a distal portion that extends distally from within the outer tube and a proximal portion affixed to an inner surface of the outer tube, the outflow conduit being defined at least in part by a space between the proximal portion of the tip element and an inner surface of the outer tube. In the method, one or more thru-holes may be disposed in the outer surface of the assembly distal to the inflow hole at the distal end of the inner sheath. The medical instrument may be used in medical procedures, such as transurethral resection of the prostate, transurethral resection of a bladder tumor, or hysteroscopic endometrial ablation, the procedures being well know to persons skilled in the art.
In another possible embodiment, the present invention is directed to a tip element adapted to be affixed to the distal end of an inner sheath or outer sheath of a medical endoscope, the tip element having a plurality of outflow openings disposed laterally in the outer surface of the element, the openings including sidewalls and in combination with a surface of the outer sheath or inner sheath defining outflow conduits for communicating longitudinally with an outflow channel of a sheath assembly in the endoscope.
The foregoing tip element may comprise a dielectrical material, such as ceramic. In the foregoing tip element, the openings have a distal portion for providing outflow apertures for an assembly of inner and outer sheaths in an endoscope.
In another possible embodiment, the present inventions is directed to a medical endoscope having an electrically conductive outer sheath, an electrically conductive inner sheath, and a working element. The outer sheath surrounds the inner sheath and defines an outflow channel, and the inner sheath defines an inflow channel. The outer sheath has a distal tip portion, wherein the tip portion is made substantially of a dielectrical composition and is disposed at the distal end of the outer sheath. The tip element has a plurality of outflow openings, the openings including sidewalls and, in combination with a surface of the outer sheath or inner sheath, defining an outflow conduit. In the assembly, the working element holds the outer sheath and inner sheath in a position such that the distal end of the inner sheath is proximal to the inflow apertures for the outflow conduits and the outflow conduits merge with an outflow channel at a position proximal the inflow hole at the distal end of the inner sheath. The working element includes a portal for receiving an active cord for a throughput device.
In the foregoing endoscope, the tip element may comprise a ceramic tip. In the foregoing endoscope, a portion of the outer sheath proximal the inflow at the distal end of the inner sheath may contain a plurality of outflow holes directly communicating with the outflow channel. In the endoscope, the working element may hold the outer sheath and inner sheath in a position such that the distal end of the inner sheath is proximal to the inflow apertures for the outflow conduits and the outflow conduits merge with an outflow channel at a position proximal the inflow hole at the distal end of the inner sheath
In another possible embodiment, the present invention is directed to a continuous flow endoscope, such as a resectoscope, used with an electrosurgical throughput device. The endoscope has a dielectrical or insulated tip portion attached to an outer sheath. The insulated sheath tip has a plurality of axial grooves circumferentially spaced about at least a portion of its outside surface such that irrigant outflow can occur from the very distal end of the outer sheath, through openings at the juncture of the insulated tip and the outer sheath tube, and then through the outflow channel between the inner and outer sheaths of the continuous flow sheath assembly, and then out of the device.
Many of the various features of novelty that characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objectives attained by its use, reference should be made to the accompanying drawings and descriptive matter in which its preferred embodiments are illustrated and described. In drawings, like reference numerals identify the same or similar elements.